1. Field of the Invention
The present invention relates to a medical irradiation apparatus and more particularly to improvement of a medical lighting installation such as a hardening apparatus of prosthetic photo polymerization resin, an intraoral lighting installation and the like in the dental treatment field.
2. Prior Art
In dental treatment, there used are a photo polymerization device for rapidly hardening the prosthetic photo polymerization resin in a tooth, an irradiation device, being attached to several kinds of handpieces or individually, for irradiating an objective tooth for treatment in the oral cavity, a dental light (shadowless light) standing at the side of a treatment bed for irradiating the oral cavity, and the like. Such a light is required to condense the light in a narrow oral cavity and is different from the light used in other fields which is required to illuminate wide area.
Halogen lamp and a xenon lamp have been used as the light source of the above-mentioned irradiation device. Recently used is a light emitting element which has characteristics of a long operating life and little electric power consumption comparing with those lamps like LED (light emitting diode), a semiconductor laser, and so on. Such a light emitting element like a LED and a semiconductor laser is provided in the form of a mounting device sealing a naked chip cut out of a wafer in a case or in the form of a bear chip.
In case of the above-mentioned irradiation device, more particularly photo polymerization device, for dental use, it is required to be high power for reducing the irradiation time in addition to condense the light on a small area because of its characteristics. Further, because it is used in a small area like the oral cavity, it is desired to be small, light weight, and compact.
The above-mentioned light emitting element like LED and a semiconductor laser is designed to distribute light in a wide area, so that it is commonly applied in other field which is required to be widely illuminated, however, the illumination intensity per a unit area in the irradiation field is small. Because the output per one element is small, the number of light emitting elements may be increased in order to obtain a desired light volume, however, it goes against the requirement of downsizing. The applicant of the present invention has proposed a medical irradiation device for solving the conflicting problems of high power and downsizing in JP-A-2002-306512 and JP-A-2002-360605.
The medical irradiation device disclosed in those prior arts uses plural light emitting elements and applies a light condensing means or improves the shape of a light introduction means is improved in order to effectively use the light emitted from each light emitting element, thereby enabling irradiation with a large light volume per a unit area. Its practical value has been highly evaluated. Although the light emitting element doesn't generate heat as a single body, if plural elements are used, its heat generation isn't ignored. Such a heat generation isn't preferable to a dental irradiation device which often contacts with gum and cheek, so that a cooling means is further provided for cooling the light emitting element in the prior arts.
According to the above-mentioned medical irradiation apparatus, it isn't considered that the photo polymerization device for hardening the prosthetic photo polymerization resin filled in a tooth forms the beam pattern which uniformly irradiates light from the surface to the deeper area of prosthetic resin. Therefore, those inventions are not enough in the sight of effectively and homogenously hardening resin and a drastic improvement is required. Further, the medical irradiation apparatus disclosed in the above-mentioned prior art has achieved high power and downsizing and also has taken a measure for preventing heat generation. Therefore, its practical use has been highly evaluated, however, the following problems have been pointed out. Namely, the above-mentioned cooling means mainly acts on the substrate of the light emitting element, and it doesn't actively cool the front (light emitting side) of the light emitting element, the light condensing means, or the light introduction means. Accordingly its cooling effect has not bee enough. Specifically, because the light condensing means and the light introduction means which are provided at the front of the light emitting element often contact with gum, there causes an obstacle for medical treatment if heat generation of these means is restrained enough.